The parties entered into an oral contract in June, under which plaintiff agreed to construct a building for defendant on a time and materials basis, at a maximum cost of $56,146, plus sales tax and extras ordered by defendant. When the building was 90 percent completed, defendant told plaintiff he was unhappy with the whole job as ‘‘the thing just wasn’t being run right.’’ The parties then on October 17 signed a written agreement lowering the maximum cost to $52,000 plus sales tax. Plaintiff thereafter completed the building at a cost of $64,155. The maximum under the June oral agreement, plus extras and sales tax, totaled $61,040. Defendant contended that he was obligated to pay only the lower maximum fixed by the October 17 agreement. Decision?